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Re: Inexpensive M/S setup for experimentation?

Subject: Re: Inexpensive M/S setup for experimentation?
From: "Eric Benjamin" ericbenjamin2
Date: Mon Aug 30, 2010 10:24 pm ((PDT))
1) How bad is the figure-8 pattern on the M179?
It's about the same as other microphones of equivalent size.  That's becaus=
e
it's the size of the microphone capsule that largely controls how the patte=
rns
deteriorate at high frequencies.  I do own a pair of M179s but I haven't us=
ed
them much because my brother-in-law has had them for the past five years.  =
I had
almost forgotten that I had them!

My microphone of choice for the side microphone in MS has always been the
Schoeps Mk8.  That's because it's an excellent microphone and I was able to=

borrow them from work.

2) Why is the self-noise of all of the capsules listed below so bad?
A figure-eight condenser microphone has a couple of strikes against it in t=
he
SNR department.  It operates in what is called resistance-controlled mode; =
the
diaphragm resonance is at middle frequencies and the design of the backplat=
e is
such that there is a ton of damping.  Having the resonance of the microphon=
e
diaphragm at middle frequencies sounds like a terrible thing, and it would =
be if
there were only an ordinary amount of damping.  That would give a response =
that
was just a big haystack in the middle of the audio range.  But the damping=

depresses the resonance so much that the response looks like an upside-down=

bathtub.

That damping lowers the sensitivity of the microphone, which in turn means =
that
the signal, relative to the noise of the FET, is small.  And furthermore th=
e
noise of the damping itself may become a contributor to the overall noise. =



The Sennheiser MKH30 is an outlier, and I believe that the reason for that =
is
that Sennheiser doesn't use as much damping, which would tend to leave a
midrange peak, except that the electronics of the Sennheiser MKH series has=

equalization in it.  If any of you are Sennheiser experts and have an
alternative explanation I'd like to hear it.

Eric






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